UTS Science in Focus: The Science of weight loss

UTS Science in Focus: The Science of weight loss

Facilitator: Thank you for coming along. This
is going to be a lot of fun, because had you told me about two years ago that I would be
standing in front of nearly 700 people talking about weight loss I would have laughed my
head off, because I didn’t know the first thing about it.
For those of you who watch Catalyst you might have seen last week we had a little story
about this. We’re going to elaborate on some of that tonight. If you weren’t watching Catalyst
last week then tonight we’re going to answer a really weird question. When you lose weight
where does it go? I can’t believe that – it’s not a question
that we all just know the answer to. Now if there are young people here they know me from
another show. I pop up on this program – it’s called Studio 3.
[Video plays in background] Facilitator: I blow things up – I have a lot
of fun – they call me The Surfing Scientist on there because I do surf. I do this kind
of thing. [Video plays in background]
Facilitator: That’s a rubbish bin with some liquid nitrogen in a bottle and 1500 ping-pong
balls exploding. I do a lot of work with kids, which I think may have helped me cotton onto
this question in the way that I did. I visit lots of schools. So I’m not just doing stuff
with telly. I have been to – well, just in the last little while just these few schools
here, this is all this year. There’s a few more. Probably been to about – what is it
now? We’re up to something like 30 to go this year. It’s up to about – it’ll be 100 by the
end of this year. So I’m a busy little camper. But my first job was as a physicist, working
in the laser industry. I used to make the optical coatings that go on the ends of laser
beams – well, not laser beams, laser tubes. So here’s a laser, it’s a helium neon laser,
and the little bits of glass that go on the end there are what I used to make.
But then I left the – so I studied physics at QUT and then I did a grad dip at ANU and
I’ve worked as a lecturer with primary school teachers at Griffith University. Very soon
I’ll be doing some guest lecturing with my new best friend who’s here this evening, Professor
Andrew Brown – I’ll introduce him to you later, who is the first person that I really bounced
this idea off on TV and that’s what went to air last week.
But look, let’s get cracking. This is how it all started for me. About two years ago
I went to Fiji with a friend, went surfing and I noticed that I had a gut, which I wasn’t
super stoked about. So I did what you’re meant to do – I started at 86 kilograms and did
what they say – eat less, move more. I was five kilograms overweight – that’s pretty
heavy. So in 11 weeks it was very easy, just ate less, moved more.
I’m not a hero, I don’t want any rounds of applause for that, but here’s what I did next.
I drew a little graph – because I was very excited – and here’s some Year 8 mathematics.
Plotted the line and figured out that I was losing 85 grams per day, which is quite a
significant little amount. It’s not the most you can lose – we’ll get to that in a minute.
But I extrapolated and saw that hey, if I keep doing this I’ll be at my target weight
of 70 kilograms by around about July that year. So that worked our really nicely.
Here’s what really happened. That’s the graph. This is what it looks like. It’s weird. This
was taken at the beginning of 2013. This freaks me out to this day. There you go, look at
that, bizarre. Look, absolutely weird. So anyway, where did it go? That was the big
question that I had. I didn’t know where it was going at first because I’m not a biochemist
I should say, but these blokes here won a Nobel Prize for figuring out a huge chunk
of this. So I don’t want to take any credit for the science of other people. I didn’t
work any of this stuff out. Hans Krebs and Lipman figured out some really
serious stuff but no one’s really worried about it the way I worried about weight loss,
as far as I can tell. When you ask around here’s the kinds of answers you get.
[Video plays] Facilitator: So that’s pretty much the answer
you get from anyone you ask that question to. We’ve asked some interesting people. I’ve
asked dieticians, doctors, high school teachers, personal trainers, you name it, people don’t
really know where the weight goes. So when you’re standing on the bathroom scales and
10 kilograms are missing where in the universe are the 10 kilograms? That’s what we’re going
to talk about tonight. So to get there we should have a think about
what is fat? Look, we’ve known what fat is for a long time but I’m going to just show
you one researcher who did some great work. Jules Hirsch, he’s an American, he did some
terrific research which gave us a very useful equation which we’ll get in just a minute.
He’s published this paper in 1960. Studies of Adipose Tissue in Man. He went and looked
at well what is fat precisely? He knew what fat is, it’s triglycerides, but what’s the
chemical formula precisely? So I’m just going to remind you that you know a fair bit about
this already. You already know this formula. That’s the formula for…
Audience: Water. Facilitator: What’s the formula for carbon
dioxide, it’s C… Audience: CO2.
Facilitator: Thank you. So you actually pretty much know – well, you know the three elements
that you need to know about for human fat. So here’s what human fat is. Fifty-five carbon
atoms. This is the average fat molecule. One-hundred-and-four hydrogens and six oxygen atoms. We know that
thanks to Jules Hirsch and that number has been recently reviewed and it’s still remarkably
accurate, so yippee-aye-a. Now if you go and learn a little bit about
triglycerides and how they’re put together – they’re made of three fatty acids stuck
to a glycerol backbone. I’m not going to bore you too much with all the details. However,
there is a bit of variation in the number of atoms. They all do very much the same thing
when they’re stuck together chemically. But there is a little bit of variation. So you
can have 36 carbon atoms instead of 55. But look, the average molecule of fat in your
body has 55 carbons, 104 hydrogens, six oxygens. Now, that means that the difference between
looking like that and like that – literally it is, that is the difference, C55 H104 O6.
Or if you’re a lady, the difference between that and that, there you go, C55 H104 O6.
Fascinating, isn’t it? So where is it hanging out? Well, here’s a
real quick introduction to where it sits. Under your skin, under your dermis, so you’ve
got your epidermis then your dermis, under there is a layer called subcutaneous fat,
you all know about that, that’s what hides your six-pack, if you can’t see it. It’s that
subcutaneous fat. It’s what stops all the visible muscles – you can’t see their defined
edges because of that subcutaneous fat if it gets too thick.
So there’s your dermis, your epidermis and subcutaneous fat there. Now this stuff is
cells call adipocytes. That’s the name. Meet your enemy if you want to lose weight – it’s
not your enemy, you actually have to have this stuff. It’s terrific. Humans wouldn’t
be what they are without it. So it’s not bad at all but it’s easy to make them a little
bit too big. So they’re called adipocytes and here’s something
that’s worth knowing about – there’s another type of fat that’s not under your skin but
in around your organs, it’s called your visceral fat, and we’ll probably end up talking about
this a little bit tonight. Visceral fat is called the bad fat. We’re just starting to
learn a lot more about the fact that it’s an endocrine organ. It’s pumping out hormones
and some of those hormones seem to be problematic if there’s too much of that abdominal fat.
But we might get to talk about that a bit later, because first of all let’s just have
a look at these little adipocytes. So these are adipocytes under a microscope
and all that white stuff is this C55 H104 O6. Now I’m told that all cells can have lipid
droplets in them but you’re adipocytes, they’re full of nothing but essentially. They’ve got
a nucleus and maybe one or two, I don’t know how many mitochondria, but not many, and the
rest is just taken up by this massive blob of fat. Look, there’s heaps of them here.
So that’s what it is. That droplet is starting to be studied as well. This is fascinating
that there’s so much yet to be learnt. There’s a paper here not just fat, the structure of
that lipid droplet, and we still are learning a lot about the nature of that fat that’s
in your adipocytes. So there’s another question that comes up
– if you talk to personal trainers and a lot of people they will say oh by the time you’re
20 you’ve got his number of fat cells in your body and that won’t change. However – and
that’s old rhetoric – dogma really from a while ago because it turns out that that’s
not true. You can grow new adipocytes and you do grow new adipocytes all the time.
So if you put on weight – they did this study where they overfed people with carbohydrate,
they all put on some weight and lo and behold what happens? This is the question they were
wondering. Do the cells that are there just get bigger? Do they fill up with this C55
H104 O6? Or do you grow whole new ones? The answer is, it’s a combination of the both
and it depends on which part of your body. For women it was mainly, in this study, around
their abdomens. The adipocytes that were there got bigger but they also grew brand new ones
in their upper legs. So it’s a very complicated story. There is more to it. You can lose fat
cells as well. So apoptosis is when cells die, and they die
all the time. So there is so much more. I’m just whetting your appetite here, because
I wanted to show you where this stuff goes when you lose weight. So C55 H104 O6, here
comes the equation that is called weight loss, this is it. You’ve got to inhale – to get
rid of that fat you’ve got to inhale some oxygen and then you will turn it into those
two chemicals you already knew about – it becomes water and carbon dioxide. That water
can go out as urine or sweat or it could go as saliva or breast milk if you happen to
be feeding, or it could go in your faeces or your tears. It could become pus – probably
better not to think about it. But let me show you what we’re talking about
here. I’ve got some carbon dioxide and water for you to have a look at. It’s in this container
here. I’ll just put on a glove. So I have some frozen carbon dioxide and I have some
water, H2O and CO2. This is frozen carbon dioxide and hopefully it’ll fit in there.
If not I’ll just snap a bit off. Right, when you chuck it in water it bubbled.
You’ve seen this a million times. So had I. I never realised I was looking at what fat
becomes, but there you go. That’s what it becomes. Isn’t that amazing? When you lose
weight it becomes this. I reckon that’s amazing. Now that’s what fat’s made of, but that’s
not fat, obviously. So how does it become fat? Well, CO2 and H2O it all happens in plants,
right. The fat in your body was first photosynthesised by a plant and it turned it into sugar – we
might talk about this a little bit more in a minute – then the sugar may have been turned
into fat in the plant. Or you might have eaten that sugar and your body might have turned
it into fat but essentially it started off as this and its plants that put it together
and then you and I eat it and off we go and put on some weight. Totally amazing.
Now, this little arrow here is simplifying something called biochemistry which takes
three years at university just to get your undergraduate in. So it’s not an easy subject.
In fact it’s incredibly complicated and I’m still in awe of anyone who does well in it.
But let’s focus on where these kilograms go. We’ve got kilograms, kilograms, kilograms.
Energy is what most people think that the fat becomes. A lot of people think that fat
just turns into heat, that’s the answer you get. Most of the doctors I’ve asked said it
just turns into heat. Well it doesn’t turn into heat – you get some energy out. But you’ve
got to have the same number of atoms afterwards that you started with beforehand. So it’s
interesting. Now we’ve measured that in kilojoules and
look, it can become heat or you can use it to move or you can use it to think. You can
use it to do all sorts of stuff. But that energy is actually sunlight. The energy in
the food was put there by a plant putting carbon dioxide and water together. So we’re
all running on sunlight, that’s really cool. If you’re a bit of a hippy this will really
ring your bells. Anyway, this heat stuff let’s just talk about
that for a second. Because let’s get the difference between mass and energy really clear. This
is the best way I can think of. I’ve got these little toys – I found them at a toyshop not
that long ago. They’re these little jumpy toys. You can push them down and the suction
cup sticks to itself. It’s got a little foot. If you stick it down it then jumps up in the
air. Isn’t that great? Well, what’s that got to do with anything?
I’m going to use it to clarify what the difference is between mass and energy. So think about
this for a second. If I put one of these things on some scales and measure it, which I have
done, they weigh about six grams. But if I push it down do you reckon it weighs a different
amount or would it weigh exactly the same? Everyone gets this. It’s exactly the same.
So the weight doesn’t change, it’s still six grams.
Now, while that spring is pushed down it’s got some energy stored in it. It’s so easy
to figure out how much that is because all you’ve got to do is measure how high it jumps
– this is high school physics – potential energy is mass times gravity times height.
So we can calculate precisely how much energy there is stored when you push that spring
down – and it’s about 0.03 joules, which is 0.0004 kilojoules. If you really like calories
– this is the only thing I’m going to talk about calories tonight then we’re going back
to SI units. We’re not in America. But there you go for the calorie counters.
Now by the way, in case you want to know well what is that worth 0.003 kilojoules, let’s
compare that to what’s in an ice cream, 1181 kilojoules. So there’s enough there – that’s
40 million times the amount of energy that’s in this spring when you push it down, which
lets it go half a metre high. Your body takes quite a bit of energy to operate. It’s incredible
how much energy we use. So isn’t that fascinating. Now hopefully having seen that you’ll never
be confused by this energy business again. Energy is just this amazing stuff that you
can’t see, touch, taste, feel. It’s just a unit of measure. It’s the same energy – same
units of energy in a spring as it is stored in food.
So let’s move on and see what’s going on here. So here’s the – the weight loss equation is
fascinating. If you do the stoichiometry. So what I mean is to get rid of 10 kilograms,
let’s say, of fat – if you do lose 10 kilograms by the way you’ll lose some other mass as
well – not just triglyceride, but we’re just going to focus on triglyceride and we might
come back to that as well. So how much would you need of all these other things and how
much would you get. So this is called stoichiometry. It’s Year
10 science. Last week on Catalyst when we did this we edited out a very critical sentence
of mine and a lot of chemists out there thought that I didn’t know this bit and oh boy, did
I get in trouble. I’ll talk to you about that in a minute as well. But look, to do this
any year 10 student should be able to do this by going to the periodic table of the elements
and just doing the maths. You’d have to inhale 29 kilograms of oxygen to get rid of that
10 kilograms of fat and you’ll get 28 kilograms of carbon dioxide, 11 kilograms of water.
Look, we’ve been able to figure that out since the ’60s. That equation’s been doable in all
that time and yet for some reason – I don’t know why – but no one ever bothered to really
put it out there. I reckon that is absolutely fascinating. So anyway, it means that before
and after you lose weight there will be precisely the same number of atoms in the universe.
It doesn’t change, right? To change the number of atoms in the universe you’ve got to do
nuclear physics. You are not a nuclear reactor – you’re a chemical device. So the number
of atoms won’t change. So by the way, if you lose 10 kilograms there’s
320 kilojoules in that amount of fat so that’s enough to keep you running for 37 days. By
the way in case you were wondering, yes, you can just not eat. Here is a paper called features
of a successful fast of 382 days duration. This bloke called patient AB didn’t eat for
382 days. That’s a year and 17 days. Don’t try this yourself without close supervision.
But here’s what that paper says. Patient AB was 27, he weighed 207 kilograms at the beginning
and he got down to 81.6. So he lost 125 kilograms. That’s 330 grams a day. I lost 85 grams a
day. So this is roughly the theoretical maximum that you can lose, right?
So when you hear people rabbiting on about how quickly can you lose huge amounts of weight
just compare it to this guy. That’s as much as you can hope to lose and that is very intense
and I don’t think anyone should try it. It’s crazy, because it’s dangerous as well.
So he was given multivitamins, some vitamin C, some yeast. It’s all in this paper. So
if you want to get more details you can just grab this paper and read it. He was given
water or black coffee, non-caloric fluids. In other words, fluids without any energy
in them. So he was still only 88.9 five years later
after this paper was published, so he kept the weight off as they like to say in the
game. But don’t try it please because it can be fatal and there are five cases reported
in that paper alone of people who died trying. He was supervised by doctors; he had his urine
tested regularly and blood samples taken. He needed potassium from days 93 to 162. He
needed some sodium from days 345 to 355. No other treatment was given. He was an outpatient.
37 to 48 days between stools. That means going to the toilet kids. Yeah, because if you’re
not eating fibre there’s nothing really to [whistles] out the other end. So fascinating.
Now, back to our little equation – because this gets better. I’ve got more demos to do
too. So here’s my question, right? So that was all just how you do chemistry. But I had
this weird way of thinking about this because I was losing weight and I rang around wondering
well okay, if I start with 10 kilograms I want to know out of the 10 kilograms – not
the oxygen but the fat – how much of that will come out of my lungs as carbon dioxide
and how much of it’s going to become water. That’s my question.
So the first bit is easy – all of the carbon atoms will go into carbon dioxide. All of
the hydrogen atoms will go out as water – simple. But to get this number really accurate you
need to know what happens to these six oxygen atoms. The question is, are they going to
go out in the carbon dioxide or are they going to come out in the water that you excrete?
This took ages. I was on the phone ringing around. I rang my friend, Professor Brown,
but he was overseas on sabbatical so I got one of his colleagues, didn’t know the answer.
I rang Monash Uni, got another professor there, didn’t know the answer. I rang Flinders University,
no, didn’t know. Also we were wondering why do you want to do this. This seems like a
pointless thing to do. Well, I didn’t think it was pointless. So
I pursued this question. I was like a dog with a bone. The people at Catalyst remember
I was just fixated on this – a little bit obsessed. One Sunday morning I found this
paper. It’s called the fate of utilising molecular oxygen and the source of the oxygen, of respiratory
carbon dioxide, studied with the aid of heavy oxygen. What does that mean?
Well, it was published in 1949. So this is old, beautiful, wonderful biochemistry. Here’s
a picture of what they did. There’s a mouse which they have injected with heavy water.
So it’s water in which the oxygen atom has been labelled with a couple of extra neutrons.
So it’s a heavier form of water, or a heavier form of oxygen. So they pumped it in, in the
form of water. Lo and behold it turned up in the exhaled carbon dioxide. Which means
that water and carbon dioxide molecules in your body are swapping their oxygen atoms.
Why do they do that? Well, it’s because of this equation here. Water plus carbon dioxide
gives you carbonic acid. That’s what gives water that prickly sensation when you scull
fizzy mineral water. It’s the carbonic acid forming in your mucus membranes as a bit of
carbon dioxide dissolves into it; it makes an acid which irritates you. Which, again,
fascinating. So that reaction is sped up in your body by
an enzyme. But look, I’ll show you a little demo that every kid should see at school.
I’ve got some phenolphthalein – it’s a pH indicator – in this water. If you add some
lime water – so this is just builders’ lime from a hardware store. If you add that to
this phenolphthalein stuff then whoop-dee-doo it goes lovely and pink.
So I’ll just show you what this stuff’s doing and then we’ll do the actual demonstration.
So when you put something which is alkaline in here it turns pink. If you put in an acid
like, for instance, vinegar then the pH will go down. This is acetic acid. Give it a swirl
and it goes beautiful and clear – how lovely. If you put in another kind of base, like for
instance your dishwashing powder from your dishwasher machine – this is quite alkaline,
so you pour a bit of that in, and it will very rapidly turn it a beautiful fuchsia.
If you put in a little bit of citric acid it goes back to clear again. Whoop-dee-doo.
So no matter what the acid is this lovely stuff will change colour if it goes alkaline,
lovely fuchsia. Now I’ll put some more builders lime in some
more phenolphthalein and we’ll give it a little swirl. I’ll show you this little fact of nature.
When you exhale out comes some carbon dioxide. Every kid knows that fact. The carbon dioxide
came from your mitochondria. It’s where – in every single cell this happens. I love this.
So then it goes to your lungs and watch this. [Conducting activity]
Facilitator: Thank you very much. Now, I’m not the first person to have done that. Michael
Faraday did a very similar demonstration back in the 1800s. He started the Royal Institution’s
Christmas Lectures for children. If you’ve never looked at them please check them out.
But what we’ve just demonstrated is that when you exhale out comes carbon dioxide and it
reacts with water and forms carbonic acid which decreases the pH of the water.
Lo and behold, this is how your brain knows that you need to breathe soon. Because in
your body, in your hypothalamus, you can detect the pH of your blood. When you’re panicking
under water and you want to get to the surface because you’re running out of breath, it’s
because of this reaction going on in your blood. Dropping the pH of your blood. Isn’t
that amazing? So you don’t detect that your oxygen levels are down, you detect that your
carbon dioxide levels are going up. Amazing. I didn’t learn any of this stuff at school
and I was a captive audience, as you all were. For 12 years I attended school, didn’t see
any of that. Something to think about, I think. So that was a lovely little demo. But back
to our – so we’ve found something out here. The paper that I found helps me to answer
this question, right. So what’s going to happen to these atoms? So we know that the 55 carbons
are going to come out as carbon dioxide, 104 hydrogen atoms are all going to become water.
But from that paper I could deduce that four out of those six oxygen atoms will go out
in carbon dioxide molecules and the other two will go out with water. That’s because
it doesn’t matter what they first become; they get swapped in your blood. Before they
get to your lungs, no matter what they were to start with, they’ll just end up in that
two to one ratio that they exist in these two substances, carbon dioxide and water.
So yippee, you can solve the equation. This is fantastic. The answer is right here.
It’s 84 per cent of the mass in a triglyceride molecule becomes carbon dioxide and 16 per
cent of the mass becomes water. So here’s the big fact, when you lose 10 kilograms 8.4
of them depart your body via your lungs. Your lungs are the major excretory organ for fat.
Who knew that? Not many people. Well now you do. One-point-six kilograms becomes water
– and water can come and go rapidly, right? You can drink a litre of water and put a kilogram
on like that. So carbon is the game. That’s where you want to get rid of the carbon for
weight loss. Water comes and goes very rapidly. Now, there’s a few frequently asked questions
that I should answer at this point, one is can I just breathe more. You’d be amazed how
often I get asked that one. The answer to that is yes you can just breathe more but
you’ll start to feel dizzy because you’ll be hyperventilating and you could well faint,
but go if you like. Frequently asked question number two is does
eight loss cause climate change. That’s a concern because if you think that you definitely
don’t understand what’s causing climate change as well as you should. So I’m not going to
answer that except that it’s wrong. A third not frequently asked but should be
frequently asked question is how does my maths work when you’re in ketosis, which is when
you go on a very low carb diet and your liver starts to make things called ketone bodies
out of your fat and you burn them differently. They’re water-soluble. Some of them can come
out with your urine. I haven’t done the maths on that. One day maybe we’ll measure some
people’s urine and we’ll see just how much carbon is coming out of their urine. But look,
that’s pretty extreme. I’m not here to advocate any kinds of diets. So we might talk about
the ketogenic diet a little bit later but let’s move on, because I’m not all for that.
So the idea is if you want to lose weight all you’ve got to do is you’ve got to eat
less and move more. This is actually the only way that it’s possible but it’s become controversial.
Some people don’t believe this, which makes me giggle, because it’s the only way. You
will lose weight by breathing and you’ll gain it again when you eat.
So this is where – let’s talk about breathing just quickly because you might think about
this later. In every breath about nine grams of carbon comes out of you. That’s just carbon.
The carbon dioxide weighs a bit more. But the carbon is coming out through your lungs
and it’s about nine grams per breath. I’ll just show you that this is true. Here’s a
balloon [blows up balloon] and a bit more of my breath. I’ve been doing this demonstration
for nearly 20 years – actually maybe a little bit more. It only occurred to me literally
last year that this is weight loss that I was looking at all that time.
So here’s a beaker which I’m about to fill with liquid nitrogen. I’ll show you the liquid
nitrogen just so you get a good look at it – because everyone loves this stuff. So it
is very reminiscent of water – just clear. It’s got bubbles in it because it’s boiling.
It boils at minus 196 degrees Celsius, which blows a lot of people’s minds. It’s got a
much lower boiling point than water. Well, there are other substances that have much
higher boiling points than water. So gold – you can boil gold. My first job out of uni,
making optical coatings, I used to boil gold in a vacuum chamber. You can do it.
So here we have nitrogen in its liquid form and I’m going to pour some onto this balloon
which will make the balloon very cold, obviously, and it doesn’t pop the balloon, which is fantastic.
Something amazing’s happening though. The molecules inside the balloon are losing some
of their kinetic energy so the balloon collapses because the pressure inside is decreasing.
It’s decreasing because when you cool a molecule down all you’re really doing is slowing it
down. So these ones are losing some of their kinetic energy. Now I can just – I can touch
the balloon without wearing gloves, because it’s not a good conductor of heat.
So I’ll pour a little bit more on. Now what’s happened in the balloon is just amazing. The
oxygen has all turned into liquid oxygen. Because that happens at minus 183 and we’re
at minus 196, even colder. So I’ll show you some liquid oxygen. You don’t
use all the oxygen when you inhale, you only use a little bit of it. Twenty-one per cent
of the air going in is oxygen and 79 is nitrogen. When you exhale there’s still about 16 per
cent of that air is oxygen. So it’s in here. The other bit, the four to five per cent,
is carbon dioxide. That, if I hadn’t eaten any food in the last few days, would all be
triglyceride that’s been metabolised. Maybe a bit of protein – hopefully not, you don’t
want to burn that stuff. So let’s take a look. The balloon is droopy
and saggy. The top is full of nitrogen. If I get it clear then you’ll see some liquid
in there. You see that? At the back it might be a little bit tricky. But there is some
oxygen in there and it’s swirling around and very rapidly turning back into gas. So it’s
all disappeared now. Now we’re left with some powder. That white powder is carbon dioxide,
it came from my mitochondria and it used to be food – and I ate it probably yesterday,
maybe the day before. When you blow on it, it vanishes.
So if you’re wondering where you food goes, mate, it comes out of your lungs. Food does
not go down the toilet. So here’s another question for you, what’s the difference between
digestion and metabolism? Ask your friends. They use the terms interchangeably. Here’s
how I get the message across to little kids. I show them that look, here’s a lolly and
here is a pool noodle. If I put the lolly in the hole that runs through the pool noodle
it can fall all the way through and it appears at the other end.
So while I have it here I say to the little kiddies, right, where’s the lolly kids and
they’ll say oh it’s in the noodle. But then you say, well hang on, is the lolly in the
foam that the noodle is made of and they all say no, it’s not. It’s in the hole that runs
through the noodle. Same with food, when you swallow food it’s not in your body, it’s in
the hole that runs from your mouth to your butt and whatever comes out the other end
didn’t get into you. So digestion is getting the lolly into the foam.
That’s a pretty amazing process. It’s very complicated and there are lots of steps. But
once you have digested it it’s no longer in the hole – the only thing that comes out the
other end there, into the toilet bowl, if fibre from plants that you couldn’t digest,
and bacteria that have inhabited your digestive tract.
So that’s the difference between digestion and metabolism. The first step is digesting,
getting it into your blood, then you metabolise it in your cells. That’s where you split these
molecules back up. Now while we’re on the topic of sugar I’d
better quickly show you what we’re talking about here. If you drink a bottle of soft
drink this big and wonder why you might be putting on weight if you’re drinking one of
these every day – I’ll just show you something amazing. If you do the maths that much soft
drink – it doesn’t matter what brand, it doesn’t matter what flavour, it has about 17 teaspoons
of sugar in it. You can do the maths if you know that a teaspoon of sugar is four grams.
So I’ve got a metric teaspoon here. You can count along here. I’m going to show you what
17 teaspoons of this stuff looks like – here we go. [Counting to 17]. There you go. So
if you drink that then it is the equivalent of sitting down with a spoon and eating that.
No different. In terms of your nutrition, not different.
Exactly the same. Why didn’t I see that at school? I still haven’t seen this at school.
I haven’t seen it on any TV program. I haven’t seen it anywhere. Why don’t people do demos?
I don’t get it. But please show everyone you know that demo, particularly people who wonder
why they struggle to get rid of their weight. Because if you’re struggling with it, it’s
because you’re putting too much back in. You will breathe out 210 grams every day.
I’ve done the maths on my own body. You will take 12 breaths a minute at rest – each one
is going to take that little tiny bit of carbon with it – that’s 17,280 breaths a day and
you will lose about 210 grams every day. The only reason you don’t lose weight is because
of what you eat. It’s because you’re putting too much back in. So if you want to lose weight
just cut back. Now when I say eat, you don’t have to not
eat. You can eat food, heaps of it – you can eat a mountain of vegetables and get almost
zero kilojoules, because most of its fibre and water. So go and fall in love with food
again and figure out what you like – don’t ask me, I’m not your diet guru. Just find
out what you like the taste of that has very few kilojoules and mate, it will literally
fly out of your lungs. So look, we could do the maths on carbohydrates
– and 75 per cent of this sugar, if you do the maths, same as I did with fat – 75 per
cent of that will come out of your lungs and the other 25 per cent will become water. So
the maths is just a little bit different than it is for fat. Seventy-five per cent of sugar
you exhale if you metabolise it. Now speaking of diets, I’m not going to promote
any kids of diets, but there’s this idea of a healthy diet. Well, this bloke, called John
Cisna, he went on a McDonald’s only diet. He just ate less. But only McDonald’s. He
lost quite a bit of weight. McDonald’s only 90 day diet. I’m not advocating this but it
just goes to show that it’s actually much more simple than people think – you just have
to eat less. He went for a walk and he ate the right number of kilojoules and he lost
16.8 kilograms and his cholesterol came down and yippee-ki-yay, wonderful stuff.
So I think on that note if you’ve still got any questions about how fat gets out of you
we will be able to cover them in our chat. But hopefully from now on the mystery is over.
Weight loss claims that you hear out there you can now put them under the microscope
and say well hang on a minute, what are these people telling me that this wonder drug or
wonder food or super food can really do for me and why is it so much better than me just
not eating as much? There is nothing as simple as just cutting back on the tucker and going
for a walk every day. So there you go. Good luck with your weight loss.
I will now introduce our panellists and we will start to have a bit of a discussion up
here. So they’re going to have a chat to us – I feel very lucky to have these people and
the calibre of them joining me here on stage for a panel discussion and your questions.
So let me introduce them to you. I’m going to walk over to the little screen over there
because we’ve got three people coming to chat to you. The first one – there’s two from the
University of Technology of Sydney and my new friend from the Uni of New South Wales.
Our first panellist is Doctor Elizabeth Denney-Wilson and she’s a senior lecturer here – actually,
sorry, she’s associate professor just as of this last few weeks. So that’s a massive deal
in a person who works at a university’s career, so congratulations. I won’t introduce her
too much because she’s got a wonderful story that she will tell you. So could you please
make welcome to the stage Associate Professor Elizabeth Denney-Wilson.
Female: I’m going to put the case for prevention. Because we know that obesity risk begins very
early in life. This, unlike Ruben’s slides, is not a picture of a fat belly but a picture
of an absolutely beautiful pregnant belly. We know that even factors that happen in utero
can affect a person’s likelihood or their propensity for weight gain in childhood. So
right from the start the food choices that parents make on behalf of their children,
including whether a child’s breast fed and when solid foods are introduced and what kinds
of solid foods, these can all predispose a child to excess weight gain.
How children gain weight is also important. So this is your common garden-variety growth
chart. This one is a weight for age growth chart; these are in use all around the world.
There are a few different varieties but they’re all pretty much the same. What happens generally
speaking is when babies head off to their maternal and child health nurse or to their
general practitioner and they’re weighed and measured generally speaking most kids will
sit on a centile and they’ll stick with that centile pretty much throughout their lives.
That’s what happens to most children. But some children experience what we call rapid
weight gain. These children actually cross centiles, or go from a lower centile to a
higher centile. Sometimes this is catch up growth because
these kids might have had some retarded growth in utero for one reason or another. But in
the vast majority of cases it’s because these kids are being overfed.
When I first became interested in infant feeding when my now adult children were babies the
thing that we worried about was parents diluting infant formula because they wanted to make
it last longer. But nowadays the reverse is true and we actually worry about people overfeeding
their babies. So babies who are breastfed, they get to choose when they’ve had enough
to eat. So they have their feed, they come off the breast and their mum learns to trust
them that they’re getting enough to eat because they grow and they have the right number of
wet nappies. If only we knew this – they were obviously having the right number of breaths
as well. But when a baby is bottle-fed there’s a temptation
to ensure that the child finishes the bottle at every feed. This might involve continuing
to nag a child or wake them up or jig them around until the bottle’s finished, or it
might involve just continually coming back and forward with the same bottle until that
bottle is finished. This overrides a child’s natural instincts around satiety or fullness.
So it overrides their ability to know when they’ve had enough.
So what happens to these kids who have rapid weight gain? Well, we know that children who
experience rapid weight gain are about three times more likely to be obese when they’re
two, they’re three times more likely to be obese when they’re five and what we know is
that growth trajectories tend to track into adulthood. So these overweight toddlers become
overweight children and overweight teenagers and overweight adults. That’s when risk factors
start to appear. So I’m just going to give you a shameless
plug now. My research team – and a couple of members are here tonight – have developed
an app that’s recommended by primary healthcare providers and it provides expert advice for
parents around feeding their baby, around settling their baby without feeding them and
around helping mums to look after themselves. We are targeting disadvantages mums because
we know that they’re less likely to breastfeed, more likely to bottle feed and also because
rapid weight gain is more common in families experiencing disadvantage.
But I can hear some of you saying all right, so these kids are a bit tubby but isn’t it
just puppy fat? Well, I’m here to tell you that no, excess weight can be harmful even
if you happen to be a puppy. Speaking of puppies – I mean teenagers – this
is the work I did for my PhD where I took blood samples from 500 teenagers who were
in Year 10, so in high school in the Sydney metropolitan area. So they weren’t attending
weight loss clinics or going to see their GP or anything like that. They were just kids
attending high school. We weighed and measured them as well. What we found was that 80 per
cent of the obese boys had elevated levels of insulin which is one of the markers that
suggests that you might be on the pathway to develop type 2 diabetes.
We also found that almost half of them had elevated liver enzymes which are suggestive
of a thing called fatty live, which is exactly as it sounds – there’s excess fat sitting
in the liver. About a third of them had low levels of HDL cholesterol, or so-called good
cholesterol. I just want to remind you these were 15 year olds and they had these risk
factors already that we would normally associate with much older people and that are really
chronic disease risk factors. So I’m suggesting that prevention is better
than cure. To achieve obesity prevention we need some long-term strategies that are implemented
and not just announced. What we really don’t need is another glossy brochure announcing
what we’re going to do to limit weight gain or get people moving more. We need to target
children and their families, because that’s where we’re going to get the best bang for
our buck in terms of preventive healthcare. We also need to ensure that the strategies
that we implement are well evaluated so we can see if they’re working or not. Oh, that
spells policy. Who’s responsible for that again? Okay. Over to you.
[Applause] Facilitator: So our next speaker is doing
a form of research that I barely can get my head around. It’s a whole new field as far
as I can tell – proteomics. Just to give you a little bit of indication – I know that there
are some slides here that really pop my brain. So would you please welcome Dr Matt Padula
from the University of Technology Sydney as well.
[Applause] Male 1: I’ll start off just by saying that
when they came to me a couple of months ago to talk about this I had the same idea as
you guys had, none. But over the last couple of weeks I’ve been thinking about this, looking
into it and realising this is wickedly cool. The way that Ruben describes it was absolutely
awesome. If they had described it that way when I did biochemistry back in 1994 I probably
would have remembered the Krebs cycle a lot better. In all seriousness.
So on the left there that’s basically all of the metabolic pathways that are within
your body. So this is everything that could happen. Now what proteomics is, is basically
the study of every single protein that happens in a particular cell at a particular moment
in time. Not all of this happens at the same time. Different cells, different things happen.
So what we try to do in proteomics is we try and look at say okay, how are things changing
with disease? Because most people think of proteins as there’s my steak, okay, I’m going
to eat that, I’m going to get protein, that’s going to turn into muscle, yada, yada, yada.
But proteins are more important than that. Proteins are actually the things that do the
work in your body. They catalyse your reactions, they allow you to digest food, they allow
you to do these metabolism things. You wouldn’t be able to make carbon dioxide without all
of these enzymes. So under different disease states – and obesity
can be termed as a disease – under different disease states the level of proteins changes.
Some proteins go up, some proteins go down. So what proteomics aims to do is to look at
how these things change within a disease, because these are the things that are actually
doing the work. Cancer occurs because of protein – proteins doing different things in your
body that they’re not supposed to do. So I’ve actually over – I’ll point this way
– over this side I’ve just zoomed in on a small little bit – this is still fairly super
complicated. What this is saying is that these are the particular molecules that are being
made. These little numbers down in the middle here you probably can’t see, these numbers
refer to enzymes. So each one of these has a slightly different number referring to the
different enzymes that catalyse these particular reactions. These things can go up in concentration
or down in concentration depending on what’s going on in the cell. This is a simplified
version of this. So what happens here, this TAG, this is triacylglyceride.
This is fat. So a number of enzymes – and we have the two main ones here, hormone-sensitive
lipase and adipocyte triglyceride lipase, these are the guys that directly break this
down because triacylglyceride are insoluble. You can’t do anything with them. You need
to actually make them dissolve in water so that they can go off and do other things.
So these two enzymes are quite impotent to break stuff down. Then it all goes into this
pathway and then it ends up in the TCA cycle, which end up making Ruben’s carbon dioxide.
Now, these enzymes here have been directly related to obesity here and their expression
level is determinant. I’m not going to get into that too much any further. But what I
find interesting is that – and it’s a thing that probably anyone who’s tried to lose weight
has had to go through you’ll lose a reasonable amount of weight really quickly but then you
won’t lose anything else. It’s this particular figure that turned me onto this. I got alerted
to this not because of reading this paper where it comes from – because in this paper
they didn’t actually talk about it. They put the graph there but they didn’t actually realise
what it meant. It was a review that realised what it meant.
What it essentially says is that you will lose – no matter what diet that you’re on
they all seem to act the same. Some of them work a little bit better than others but you
lose the majority of the weight in the first two months and then after that you do bugger
all. If anything you start to put it back on. There’s a reason behind this, and the
reason is that you can quite easily lose 50 per cent of the triglycerides in your cell
but then what you’re doing is you’re actually doing – if you do this quickly and you do
it too fast your adipocytes shrink and they shrink too fast.
So your cells don’t exist and sit there in isolation. They’re surrounded by other proteins
and a thing called the extracellular matrix. If that doesn’t shrink at the same rate as
the adipocytes do you induce this stress response. So cells become stressed, just like you do
when you’ve had a bad day at work. So what happens is that when they undergo this stress
response their reaction to that is take up more triglycerides. They actually return to
a preadipose state. So they basically go back. One of the things – I do work on fat a little
bit. My interest in fat is not in weight loss, it’s actually in the fact that fat is the
richest source of adult stem cells in your body. Forget bone marrow or anything like
that, fat is where most stem cells are. So we spend a lot of time extracting out stem
cells and getting rid of the adipocytes and not even caring. But it makes sense – and
this is where you’ve got all these stem cells in there and they normally become adipocytes.
So you increase the mass of them and that’s where you get more of them. But you can make
them do other things. Anyway, I’m getting a little bit off the track.
So there’s been a lot of work now – there’s not as much out there as I thought that there
was going to be. I was quite surprised at how little research has been done. Because
fat is such an important endocrine organ. It makes hormones and things like that. The
majority of the studies about proteins have been about what those hormones do, where they
go, how they affect other organs and so on and so forth. No one’s really looked at what
happens to the fat, what happens in the proteome when you lose triglycerides.
But what seems to happen is that when you do something – and this information comes
from a paper that was published this year, they did a very clever thing where they took
fat cells and they grew them up in culture and they basically imposed calorie restriction
on them in culture. So they grew them at about 10 per cent the amount of glucose that you
would normally take up normally. What you end up seeing is the normal stuff, yes you
get increased lipid breakdown, you get increased release, you get the shrinking. But you get
89 proteins that are being changed in their expression. So they’re either increasing or
decreasing. This is not just related to proteins that
break down fat but it’s also in the structural remodelling of the cells. Cytoskeleton changes,
extracellular matrix changes to reduce the size of that. But you also get a really important
thing which is a reduced amount of inflammatory proteins. There’s a massive amount of evidence
now coming out that the main reason that people have trouble losing weight is because of a
thing called exercise salience. What it’s essentially saying is that if you
don’t exercise and you take up weight your adipocytes and your fat cells respond by producing
more hormones and more inflammatory proteins. Those inflammatory proteins stop you from
exercising. They dissuade you from exercising. Therefore, you eat more. Therefore, you put
on more adipocytes. Therefore they make more hormones and therefore, you’re less likely
to exercise. So this whole idea of exercise salience is
becoming quite interesting. What a few groups are doing now is they’re starting to look
at whether or not there are genetic dispositions or environmental dispositions to encourage
you to spontaneously do exercise. So that’s a really interesting field of research. I
think that that is probably where treatment is going to go. There’s not going to be a
magic bullet, there’s going to be what can we actually do to encourage a person to do
exercise. To make them feel good about exercise and become addictive. That’s probably all
I need to say. [Applause]
Facilitator: As I said, it’s massively complicated in the world of protein. I’d love to hear
Matt have a conversation with a gym junkie who takes whey powder to build up muscle.
We might talk about that in a minute. Now our next speaker I met through this little
process of thinking about weight loss. He was the first person I tried to ring to find
out what happens to the six atoms in a triglyceride, but he was away in Finland it turns out. I
left a message and I never heard back from him. I thought what a rude bugger. No, I didn’t.
Anyway, when we did the Catalyst story we got to meet. So I’d love you to give a very
warm welcome to my new best mate, Professor Andrew Brown.
Male 2: So thanks for inviting me today Ruben. It’s great to see Ruben in action and great
to see a wonderful audience like we have here who are obviously very interested in biochemistry.
That’s what I teach. It is, indeed, complicated. So I teach fat metabolism and my research
is focused around one particular fat, which most of you will have heard of, cholesterol.
So it’s a fascinating molecule. When you think of cholesterol it may be that
the first thing that you think about it indeed Catalyst. Because there was a couple of shows
on Catalyst last year on cholesterol where they asked a bunch of experts – not me – but
other experts, some of whom I’d never heard of before, including Dr Sinatra. So Dr Sinatra
has a very interesting website where you can learn the truth about statins and cholesterol.
You can also learn about something called grounding. So this is a direct quote from
Dr Sinatra. Putting your bare feet on the ground you soak up lots of electrons because,
as we know, the earth is negatively charged and our bodies are so full of free radicals.
So if you do feel like just kicking off your shoes and getting grounded, please do.
So Dr Sinatra I think would be a great person to have on your barefoot bowling team, maybe
great at karaoke, would do an excellent rendition, I’m sure, of My Way. But probably having him
as an expert on an official science show, maybe not such a good idea.
One of the things that they did show on the Catalyst program, which I think was very useful
– is this idea that there are two faces to cholesterol. That too much, which is what
we normally think about, can be a bad thing in terms of heart disease. But the flip side
is that we need cholesterol. So we need cholesterol. Without it our cells leak like sieves. We
need it to make steroid hormones – so to make testosterone and oestrogen. Without them life
wouldn’t be much fin – indeed, life wouldn’t be.
It’s also important in early development, which is why eggs contain so much of it. That’s
why we’ve evolved these elaborate mechanisms for keeping our cholesterol levels under tight
control. So this careful balancing act – and the Chinese have this very useful concept
of yin-yang. In scientific parlance we call that homeostasis.
So that’s what my lab is researching. It’s really how we get that sweet spot of cholesterol.
How our cells optimise and get that balance right. So they do it by controlling how much
cholesterol goes into the cell, how much cholesterol goes out of the cell and how much cholesterol
we make. So that’s the balancing act there. My lab is particularly interested in how we
make cholesterol. So this is a complicated process. So as you can see, you’ve got a two
carbon little LEGO block which you’re then building up into this complicated four fused
ring structure called cholesterol and it’s complicated. So when I first encountered cholesterol
synthesis I was like trying to navigate around Tokyo using the subway and without being able
to speak Japanese. Whereas, of course, in Sydney we do things far more simply.
So I will depict cholesterol synthesis as a typical Sydney Beach scene, where here you’ve
got a boy who’s pouring in that two carbon unit, acetyl-CoA, and you can see it flowing
all the way down to cholesterol. You see it pooling at this point here, HMGR, which stands
for HMG-CoA reductase, and that’s considered to be the rate limiting step. So it’s the
slowest step in the pathway. It’s the target of the statins.
So some of you may be on statins – chances are you’ll know somebody who’s on this drug
because they’re the best selling drug class in Australia, worth a tidy $30 billion per
year internationally. Like any drug, not without their side effects. Those side effects are
thought to be due to the fact that there is a side stream which comes off here. So that
side stream leads to a bunch of other important molecules and we’ll just call that important
stuff. So what we’ve been looking at is other enzymes
in the pathway. So there’s about more than 20 other enzymes in this pathway and we’re
looking at the regulation of each of those. So you can see this miniature Uluru SM, and
that stands for squalene monooxygenase, it’s a long name. What we’ve found is that’s another
rate-limiting step in this process which is tightly regulated. So it’s another possible
drug target that we could use to manipulate our cholesterol levels.
So back to Ruben’s big, fat question. This is a photo that we took a few months ago – actually,
a former graduate of this esteemed university took this, [Matthew Wiley]. So I think if
you think about the image that we try to present to the world – we have Bondi Rescue being
beamed around the world – so we often try to think of ourselves, I think, as a nation
of lifesavers – and even our prime minister gets into the act. Sorry, that’s too much
information. But when you think about it the reality is
that in terms of the shape that we’re getting into we’re looking more like these are our
lifesavers. Or, perhaps, we’re looking like a life-size replica of the Titanic. I thought
I had a picture here. There it is. So I guess the question is, is this our future? A race
of supersized humans devouring the planet so that pretty Sydney beach scenes like the
top picture are only a virtual tour. Just an electronic memory. I’d just like to go
back to this picture – and that’s actually me in the background. You can’t recognise
me because my head’s been swapped. You don’t believe me, do you? That is indeed me. I assure
you it is a fat suit. Thanks for your attention. [Applause]
Facilitator: Well as you can see it’s a very complicated field. So I think the first thing
that I would love to just kick off with is why do we think that this – what seems to
be a question that we could have answered 100 years ago, for the general public has
laid hidden and completely obscured by all this extra info? And why haven’t we heard
this very simple explanation of weight loss before? That it becomes carbon dioxide and
water. Did you learn it at uni? You said you did the Krebs cycle, Matt, did you…
Male 1: No, not to this extent. I remember learning it in second year biochemistry but
I certainly – it was never put in that kind of context. I think this is the problem that
we have when we’re teaching high school students – and you’d know this – we have the same problem
when we’re teaching university students is that we’re all quite happy to teach – well,
sorry. The historical thing is to teach to pass the exam or to pass the subject. Whereas
what we really need to be doing is teaching with these practical examples to reinforce
these kind of concepts so that they’re not instantly forgotten as soon as they leave
the exam room. I think that’s part of the issue. It’s just that – it’s just never been
taught in an interesting way. Facilitator: Now your undergraduate days,
Elizabeth, were – tell us about those? Did you learn this sort of stuff?
Female: Well there was beer… Male: There’s always beer.
Facilitator: There’s was what? There was beer [laughs]?
Female: There was beer, yeah. Facilitator: It’s fattening if you have a
lot of it, apparently. They say. It’s got two fixed carbon atoms in alcohol, that’s
my point. Yeah. Female: I do remember learning the Krebs cycle
but from a book. I’m pretty sure it was in The Web of Life. My husband would probably
– he’s a bit of a fan of The Web of Life as well. But I’m pretty sure that’s where I learnt
the Krebs cycle, yeah. Male: Page 312.
Female: Thank you. Facilitator: Page 312, I’ll be checking that
later on this evening. Now Andrew teaches this form of biochemistry and I’ve actually
been in the lecture where it gets taught. We’ve discussed this, but how would you describe
why people – even advanced biochemistry students don’t seem to retain this really simple fact,
do they? Male 2: Yes, I think the main reason is that
the way that we teach biochemistry is we have to cover a lot of material. It’s quite fragmented.
Individual lecturers often give different parts of the overall – well, different metabolic
pathways so it’s hard for the students – sometimes hard for the lecturers – to actually integrate
the information. I think the other thing really is that our emphasis has really been always
on how we turn food into energy. So that really has been – that’s the sort of stoichiometry
that we have. We don’t talk about mass, we talk about number of molecules and the number
of ATPs produced which, of course, is the energy – the universal currency of energy
that we always talk about in biochemistry, ATP. So I think that’s really it.
If you think about, I guess, the historical perspective of how biochemistry arose, it
arose at a time when there was – a lot – when food shortages were a lot more important than
too much food, which is the case today. So this really is, I guess, just bringing a different
perspective. As Ruben knows, we actually asked this – our students, so this was probably
120 students who answered the survey, Ruben’s Big Fat Question, after I’d actually give
the lecture on beta-oxidation of fats, which is the way that you breakdown fats.
Somewhere buried in there was talk about carbon dioxide and water being formed. When they
answered that question it was probably less than 20 per cent actually said CO2, the rest
– most of them actually said ATP, which goes back to Matt’s point that they’re going for
the exam. Or the other thing that they did is they just downloaded very bit of information
they had and just had an essay answer for a one-line question, which is typical undergraduate
student. Facilitator: It is. ATP being, by the way,
adenosine triphosphate. It’s the molecule which gets that energy out of your sugar molecule,
that bit of sunlight, and it becomes a different chemical bond and then that’s used for all
sorts of stuff in the cell. I mean it get so complicated so fast biochemistry. It took
me ages to find that carbon dioxide. There’s one more thing – I’ll just stick with biochemistry
for one second – because I’ve attended a few of Andrew’s lectures now. In one of them you
said that it’s not really quite right to say that we burn food, you say we electrocute
it. Male 2: Sure. Electrocuting probably isn’t
strictly correct either. What it is, is that. So if you think about burning fat, like I
immediately think of a candle burning or a flash in a fry pan or something like that.
So obviously the way that we’re burning fat inside our bodies, well, metabolising fat
is a lot more subtle. Luckily no flames are involved. So what we’re really doing is that
it’s – we’re ripping electrons of that fat – fat is very reduced. It’s a hydrocarbon.
We can put adipose tissue from liposuction clinics into a diesel engine and run a diesel
engine – it’s been done. So I think – so what you’re then doing is you’re shuttling down
all these electrons eventually to make that ATP. To make ATP in the mitochondria.
Facilitator: Super complicated. I’m amazed that anyone ever managed to figure it out.
We can talk about the biochemistry until the cows come home but most people don’t go beyond
Grade 10 science. So Elizabeth, you deal with actual people who…
Female: Yes, I do, whole people. Facilitator: Yeah, exactly. Who – probably
for most of us our body feels like this black box. We don’t know what goes on inside it,
got no idea. You stick food in, somehow you live. So clearly teaching the world biochemistry
is not going to solve the obesity crisis that we’re facing.
Female: I wouldn’t think it would be my first suggested intervention.
Facilitator: You’ve already said that you think preventing it is probably going to be
the solution down the track and I’d definitely agree with that. I think we’ve got a perfect
chance with every school kid. We’ve got them sitting there for 10 years at least. However,
that doesn’t help people who have got to middle age who would like to lose a bit of weight.
So what do you do with people? Female: Well it’s really complicated, as you
said. You need to eat less and move more. [Laughter]
Female: So you know all of those books that you can buy, all of the weight loss books
and all of the special drugs you can buy. Well, what they all say is eat less, move
more, they just have different ways of doing it. So some people want you to do it as a
liquid, some people want you to do it as all protein or higher fat, higher carbohydrate.
But the reality is you need to eat less and move more.
We’ve got some – there’s this really fascinating data set that’s been collected over the last
30 years and it’s been collected at the University of Denver. They’ve tracked the habits of people
who have successfully lost 30 pounds or more – because it’s the United States, so 12 or
13 kilograms, and kept it off. They’ve looked at their diets, their physical activity habits
and what kind of things they do. The overwhelming message is that they’re active for about an
hour a day – it can be as simple as walking. They keep an eye on what they eat. So nothing
as strict as weighing portions or anything but they’re mindful of what they eat. They
do some sort of self-monitoring around maybe weighing themselves once a week, that sort
of thing. Over the years the diet composition has changed.
So it’s gone to higher protein or higher carb or whatever the latest fad happens to be.
But those three things remain true; they monitor what they eat, they monitor their weight and
they’re physically active. Facilitator: It’s very simple. I wasn’t going
to dish out any advice to anyone who’s trying to lose weight but for the first three months
all I did was go for a bit of a walk on top of what I was normally doing and stopped drinking
full cream cappuccinos that I was smashing every day. So everyone’s got their own way
of approaching eating less. But it doesn’t have to be this big drag either, does it?
It doesn’t have to be a carrots and celery only thing.
Female: No. Any diet – all of the diets – so all of those diet books and all of the weight
loss products you can spend your money on, they all work if you follow them – they don’t
work if you don’t follow them – because they all reduce your calorie intake in some way.
But the best diet is the one that you can stick to, and that’s what you need to find.
You need to find your diet that works for you, that keeps your calories around the number
of calories that you’re burning every day. Facilitator: Yeah, right. So back to something
you were saying, Matt, which was – and I’m going to pick it up – this idea that if you
start dieting and you do start successfully losing weight then your body responds in this
way that just forces you to not stick with those healthy habits. So hopefully the one
thing that maybe some of these studies don’t take into account is that driving every human
body there’s a brain. If we educate that person a little bit more, rather than throwing really
complicated sounding science at them, if we just sit them down and maybe say to them look,
the only reason you’re not losing weight is because you’re eating. Atoms don’t magically
appear inside your body because you’ve got medieval curse where [makes noise] where did
that come from? You had to eat them. So maybe – do you think some of these studies
– I’ve read tons of them, reviews and they gave – they’re very complicated and it all
sounds fancy and fantastic but do you think maybe we forget that we’re dealing with people
and they can think? Male 1: Yeah, well one of the things that
struck me just sitting here and listening to Elizabeth just now is that we’re missing
one particular point and that is to be able to do this properly you need support. You
need the support of your friends and your family and things like that to be able to
stick to it. I mean if you’re in an environment where you are trying to lose weight and everyone
around you is gorging themselves stupid then you’re not going to be very motivated to do
that. The same thing with trying to get into an exercise program, trying to do that thing
a day. I mean I go out every morning and I jump the
train off at Parramatta and I ride my bike inform Parramatta to Ultimo. It takes me an
hour and 20 minutes. Some days it’s really hard to get out of bed because I’m by myself
and it’s boring. It’s hard to push yourself when you’re by yourself. So you really need
to find something where you’re actually enthused to go out and get moving and move around.
Then when you are at dinner or something like that, that you’re not being encouraged to
overeat because your mother 15 years ago told you that you couldn’t leave the table without
finishing everything on your plate. Female: Absolutely.
Male 1: I think that there’s a big support problem that needs to be addressed as well.
Facilitator: Right, yeah. That moving thing – here’s a little thing that I love pointing
out to teenagers – watch toddlers. Watch them when…
Male 1: They never stop. Facilitator: They don’t stop moving and they
laugh when they’re running, they like it. For some reason we stop running around, it’s
really weird. Male 1: It is addictive. I mean people are
going to laugh about this but there is a massive body of research out there that says that
exercise becomes addictive. It becomes a need. You can’t do it to an extreme – I’m not saying
that everyone needs to go out and run an ultra-marathon but you’ll get to the stage where if you skip
a day or two days you will start to get antsy and you’ll start to get stressed. You don’t
realise it but it’s because you haven’t done your exercise. You haven’t got that – you
haven’t got your body moving so that it has the anti-inflammatory response that having
exercise generates. It actually makes you feel good because it’s producing proteins
and chemicals that reduce inflammation and, therefore, make you feel good. So it’s worth
doing. Facilitator: Andrew, when we talk about this
exercise and all the various ways you can lose weight, still biochemically ultimately
we’re going to have to coax triglyceride out of adipocytes, aren’t we? Can you just remind
the people the first step of that – you’ve got a molecule stuck inside a cell, why is
it stuck in there? Can a full triglyceride get out of a cell? What has to happen to it
first and what causes that to happen? Male 2: Sure. Yeah, so there’s hormone signals
which usually then sense that there is some sort of energy deficit, which then stimulates
that triglyceride to start being split up by an enzyme called hormone-sensitive lipase
or – and there’s also adipose triglyceride lipase as well. So they’re just basically
splitting that triglyceride up into the fatty acids, which are part of it. Then that fatty
acid actually has to be split up too. So a fatty acid might have something like 16 carbons
and you were splitting it off every two carbons in that process called beta-oxidation. I always
think of it as being like putting a log into a wood chipper and it’s just spitting out
these itty-bitty bits of two carbon molecules. Facilitator: Totally amazing because the triglyceride
can’t, by itself, get through a cell wall, right?
Male 2: No. Facilitator: It’s got to be dismantled.
Male 2: Exactly. Facilitator: Then once it’s outside the cell
it’s put back together again and then off it goes through your bloodstream and over
to where it’s needed for energy production. I’m constantly saying to Andrew that I am
amazed that people have figured this stuff out because as you all know water, H2O, you
can write down the molecule, you can draw a picture of it – a ball with two other balls
stuck on it. But it doesn’t look like that. It looks like – we’ve got some there. It’s
a clear liquid when you’ve got a lot of it. Fatty acids don’t look like long chains of
– with Cs written on them conveniently. Somehow people figured all this stuff out. Where it
happens in mind-blowing that it happens between the membranes of a mitochondria. It’s all
really wonderful stuff. I can’t get enough of it. But hopefully we can get it into the

17 thoughts on “UTS Science in Focus: The Science of weight loss

  1. Hi, I was at this forum a few weeks ago.  I wanted to ask a question but we were out of time.  Is there anyway to contact Ruben in regards to this?

  2. I turned in to a big guy through many ways, not my fault, and few ways that could be due to age. But at the end of the day, what aggravates me, is that. People want me to go to the gym!, I always was obsessed with going to the gym. i even joined government organisations example: "(army)(Royal Marines)(USMC)".
    I took on challenges to have that diet that worked for me to make it through the day at the pace i lived to train. My point again, is that. I go to the gym. I see people i knew who claim they support me. they do not need to support me. but by claiming, or ignoring the fact i used to know them, puts me in that position of pure imagination. before me is people that live to change memories. to live a life of imagination, there for there is no real support, and i get overpowered by peoples support to want me to not be obsessive in going to the gym., not wanting me to be fit and healthy. yet. When i go to the Gym, Just having the muscle that i gained from the endurance i set about. lets me know i can do what i need to. just without the support. I need to be safe, need to

  3. So if your weight loss plateaus from the extracellular matrix not shrinking as fast as the adipose tissue is shrinking, how can we make the extracellular matrix shrink at the same rate so as not to cause stress? Or did I understand what he said wrong?

  4. This proves that lifting weights at the gym just doesn't cut it when it comes to weight loss, clearly running,cycling quite fast is necessary!

  5. 56:00..whey protein, I was excited but then Matt never spoke about whey protein, I wish I heard his thoughts on whether whey protein powder is a waste of time or not.

  6. Obesity is costing the government billions. I wish the government spent money subsidising gym and sport memberships to encourage Australians to be healthy.

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